Interlayer exciton landscape in WS$_2$/tetracene heterostructures

TL;DR

This study combines theory and experiments to explore interlayer excitons in WS$_2$/tetracene heterostructures, revealing their signatures in photoluminescence spectra and highlighting their potential for optoelectronic applications.

Contribution

It provides the first combined theoretical and experimental analysis of interlayer excitons in TMD/molecule heterostructures, detailing their spectral signatures and temperature-dependent behavior.

Findings

Identification of interlayer exciton signatures in spectra

Observation of intensity transfer from intralayer to interlayer excitons with decreasing temperature

Detection of phonon-sidebands related to interlayer excitons

Abstract

The vertical stacking of two-dimensional materials into heterostructures gives rise to a plethora of intriguing optoelectronic properties and presents an unprecedented potential for technological development. While much progress has been made combining different monolayers of transition metal dichalgonenides (TMDs), little is known about TMD-based heterostructures including organic layers of molecules. Here, we present a joint theory-experiment study on a TMD/tetracene heterostructure demonstrating clear signatures of spatially separated interlayer excitons in low temperature photoluminescence spectra. Here, the Coulomb-bound electrons and holes are localized either in the TMD or in the molecule layer, respectively. In particular, we reveal both in theory and experiment signatures of the entire intra- and interlayer exciton landscape in the photoluminescence spectra. In particular, we find both in theory and experiment a pronounced transfer of intensity from the intralayer TMD exciton to a series of energetically lower interlayer excitons with decreasing temperature. In addition, we find signatures phonon-sidebands stemming from these interlayer exciton states. Our findings shed light on the microscopic nature of interlayer excitons in TMD/molecule heterostructures and could have important implications for technological applications of these materials.